JP2992430B2 - Cable stretched car - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable-stretched vehicle for stretching electric wires and other cables between columns.

[0002]

2. Description of the Related Art Conventionally, in order to stretch a cable such as an electric wire between columns such as a telephone pole, first, a ladder is leaned on a predetermined pillar, and the ladder is climbed up and supported on an upper portion of the pillar. Attach a wheel as a member and hook a tow rope with the rear end connected to a cable on the wheel. Then, descending to the ground and pulling the rope by human power, guiding the rope to the column next to the column, and transporting the ladder leaning on the column to the column leading the rope, Lean against. Then, after climbing this ladder and attaching a wheel to the upper part of the support, the rope is lifted from the ground into the air, and the rope is hooked on the wheel. Thereafter, by repeating the above operation, the rope is hooked on a predetermined number of columns, the rope is pulled by human power, the cable connected to the rear end of the rope is pulled out from the cable reel, and the pulled-out cable is attached to each column. The cable is sequentially hooked on the attached wheel and bridged between the columns, and the cable is fixed to a cable fixing member attached to the column. In some cases, the wheel may be attached to all the posts before the rope is pulled. Further, depending on the type of the cable to be stretched, the cable may be directly hooked on the wheel and stretched without using the above-mentioned towed rope.

[0003]

According to the above-mentioned conventional cable stretching method, every time a cable or a rope connected to the cable is hooked on a support, the cable or the rope is lifted from the ground to the air or from the air to the ground. Since it is necessary to lower the work, there is a problem that the installation work is complicated, requires many work steps, and the work efficiency is extremely poor.

[0004] Further, since it is necessary to transport the ladder leaning on one support to another support, the work of stretching is further complicated. The present invention has been made in view of the above problems, and an object of the present invention is to provide a cable-tension vehicle that can easily and efficiently perform a cable-tension operation.

[0005]

Means for Solving the Problems] cable Zhang設車of the present invention for achieving the above object, a vehicle propelled, this
A boom that can be turned upright at the approximate center of the width of the vehicle
The post and the boom post support the car
A boom device that is stored along substantially the center in the width direction of the body and has a boom that connects a support cable or a tow rope connected to the cable at the tip, and a boom mounted on the vehicle body and capable of raising and lowering and storing a ladder Ladder support means, and a ladder supported by the ladder support means, the ladder support means being a holding member for holding the ladder movably in the longitudinal direction, and being held by the holding member. and when using a ladder, and a stopping a lower end of the ladder, with and a stopper a stopping state is released when the ladder of the housing by embracing member
A state in which the lower end of the ladder is held and the ladder is laid down
With the ladder to the side of the boom in the stowed position.
And below .

[0006]

According to the cable-stretched vehicle having the above structure, the cable or rope connected to the end of the boom device can be pulled in the air by running the vehicle body with the boom device raised. . Further, the cable or the rope can be held in the air by a boom device and can be sequentially hooked on a support.

Further, the ladder can be used by fixing the lower end of the ladder by the stopper of the ladder supporting means . Therefore, for example, a support member for hooking a cable or a rope can be attached to the upper part of the column using the ladder, or a cable or a rope can be hooked on the support member. In addition, when the ladder is stored, the ladder can be released from being stopped by the stopper, and the ladder can be moved in the longitudinal direction along the holding member. Therefore, the ladder can be stored without protruding from one side of the vehicle body. Moreover, since the ladder is mounted on the vehicle body, the ladder can be transported while pulling the cable or the rope.
Also, the ladder support means may be configured to hold the lower end of the ladder by a holding member.
With the ladder while holding the part and laying down the ladder
Located sideways and below the storage position boom
Therefore, when turning or raising the boom,
In addition, there is no possibility that the ladder support means and the ladder are in the way.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 and 2 are perspective views showing one embodiment of a cable-stretched vehicle A of the present invention. This cable-stretched vehicle A connects a self-propelled vehicle body 1, a boom device 2 mounted on the vehicle body 1, and a tow rope R provided at the end of the boom device 2 and connected to a cable C. The dodging device 3 that allows the rope R to pass through an aerial obstacle D that crosses the tension space B of the cable C (both shown in FIG. 14), and the ladder H mounted on the vehicle body 1 can be raised, lowered, and stored. The main part is constituted by the ladder support means 4 for supporting the main part.

The self-propelled vehicle body 1 is self-propelled by rotating the crawler 11 by a driving source such as an engine or a motor, and an operation for operating the vehicle body 1 is provided at a rear portion thereof. A part 12 is provided. The boom device 2 is provided at the front end of the vehicle body 1 in the width direction of the vehicle body 1.
A boom post 20 pivotally erected via a swivel base on a substantially central portion of the direction, the relief boom 21 which is pivotally connected to the upper portion of this boom post 20, the undulations boom 2
The telescopic boom 22 is inserted into and detached from the distal end of the telescopic boom 1 (see FIG. 3), and the bending boom 23 is rotatably connected to the distal end of the telescopic boom 22. An up-and-down cylinder 24 for raising and lowering the up-and-down boom 21 is provided on the rotation base side of the up-and-down boom 21. The telescopic boom 22 is moved by a telescopic cylinder (not shown) built in the undulating boom 21.
A predetermined stroke can be protruded from the tip of the up-and-down boom 21. Further, the refraction boom 23 is fixed so as to be integrally rotatable with a rotation axis S1 of a hydraulic rotary actuator 25 attached to the distal end of the telescopic boom 22, and can be freely rotated by rotating the rotation axis S1. (See FIG. 5). Above boo
1, the telescopic boom 22 and the bending boom 23 are shown in FIG.
As shown, it is stored along the approximate center of the width of the vehicle.
You. The operation of raising and lowering the boom 21, the operation of expanding and contracting the telescopic boom 22, and the operation of bending the refraction boom 23 can be performed by the operation unit 26 attached to the boom post 20. The boom post 20
Is configured as a tank for storing hydraulic oil.

The dodging device 3 can be remotely operated by an operating section 26 attached to the boom post 20. As shown in detail in FIG. 4, a part of the outer periphery is cut off by a predetermined length. An annular gear 31, a support frame 32 that supports the annular gear 31 so as to be rotatable around a horizontal axis, and a driving unit 33 that rotates the annular gear 31 in both forward and reverse directions. The above-mentioned annular gear 3
Numeral 1 has a tooth surface on the outer periphery, and a cut-off portion 31
A hook 31b for connecting a rope R for cable towing is attached to a side opposite to the side a through a shackle 31c. Further, the support frame 32 sandwiches a predetermined range of the lower half of the annular gear 31 from both sides by an arc-shaped sandwiching member 32a, so that the annular gear 3
1 is rotatably held. The lower end of the support frame 32 is attached so as to be able to rotate integrally with a rotation shaft S2 rotatably supported at the tip of the refraction boom 23. Further, the driving means 33 transmits the driving force of the motor 33a to a pair of driving gears 33c meshed with the annular gear 31 via a chain 33b, and rotates the motor 33a forward. Thereby, the annular gear 31 can be rotated approximately 180 ° counterclockwise in FIG. 4 via the respective drive gears 33c. By rotating the motor 33a in reverse, the annular gear 31 is inverted and the original gear is rotated. It can be returned to the position. The cut-off length L of the ring gear 31 is set to be smaller than the arc length of the holding member 32a.
1 is rotated, the ring gear 31 is
2a can always hold it. In addition, the annular gear 31 is usually arranged such that the cut-off portion 31a faces forward of the vehicle body 1.

The posture of the dodging device 3 is controlled by a posture control mechanism 5 so as to always maintain a constant posture irrespective of the elevation angle of the elevation boom 21 and the refraction angle of the refraction boom 23. The attitude control mechanism 5 moves the support frame 32 of the dodging device 3 to the rotation axis S2 in accordance with the undulation angle of the undulation boom 21 and the refraction angle of the refraction boom 23.
By rotating it around, the dodging device 3 is maintained in an upright position in which the annular gear 31 is located above the support frame 32. As shown in FIGS. 5 and 6,
A first sprocket 51 is provided concentrically with the rotation axis S3 of the up-and-down boom 21 and is rotated with the rotation of the up-and-down boom 21, and a second sprocket rotatably supported by the boom post 20. 52, a third sprocket 53 provided at an intermediate portion of the hoisting boom 21 so as to be movable along the longitudinal direction of the hoisting boom 21, and a fourth sprocket 53 provided so as to be able to move along with the third sprocket 53. A sprocket 54, a fifth sprocket 55 provided at the tip of the telescopic boom 22 and rotatably coaxial with the rotation axis S <b> 1 of the hydraulic rotary actuator 25, and a refraction boom 23.
A sixth sprocket 56, which is rotatably provided concentrically with the rotation shaft S1 and is rotatable integrally with the fifth sprocket 55, and is provided at the tip of the refraction boom 23. A seventh sprocket 57 rotatable integrally with the support frame 32 of the dodging device 3 about the rotation axis S2, and first, second, and third chains E1, which are appropriately wound around these sprockets. E2 and E3.

The base end E1a of the first chain E1
Is fixed to a first sprocket 51 and is wound around a third sprocket 53 via a second sprocket 52 in a state of being wound around the first sprocket 51 almost half a circle. E1b is fixed to the rear end of the telescopic boom 22. The second chain E2 has a base end E2a fixed to the fifth sprocket 55, and the fifth end of the second chain E2
The fourth sprocket 54 is wound around by ４ turn.
And the end E2a is fixed to the end of the up-and-down boom 21. In addition, the third
The chain E3 is wound around the sixth sprocket 56 and the seventh sprocket 57, and both ends are connected to each other via a chain bolt 59c. The sprockets and chains may be provided in two sets each for the sake of strength.

According to the attitude control mechanism 5, when the up and down boom 21 is raised and lowered, the third sprocket 53 is pulled via the first chain E1 according to the angle of the up and down, and the fourth sprocket Along with 54, the boom 21 is moved in the direction of the rotation axis S3. Then, the fifth sprocket 55 is rotated via the second chain E2, and with this rotation, the sixth sprocket 56 is rotated, and the seventh sprocket 55 is rotated via the third chain E3. Is rotated. As a result, the support frame 32 of the dodging device 3 is rotated about the rotation axis S2 in the direction opposite to the direction of rotation of the hoisting boom 21 by an angle corresponding to the hoisting angle of the hoisting boom 21. The standing posture is maintained. On the other hand, when the refraction boom 23 is refracted, the sixth sprocket 56
Is rotated relatively to the refraction boom 23. For this reason, the seventh sprocket 57 is rotated via the third chain E3, and the support frame 32 of the dodging device 3 is rotated.
Is rotated about the rotation axis S2 in a direction opposite to the rotation direction of the refraction boom 23 by an angle corresponding to the refraction angle of the refraction boom 23, and the standing posture is maintained.
In addition, the third and fourth sprockets 53 and 54 are moved to the tip side of the up-and-down boom 21 with the expansion and contraction of the telescopic boom 22.

As shown in FIGS. 7 and 8, the ladder support means 4 includes a holding member 41 having a substantially U-shaped cross section for holding both sides of the ladder H, and a holding member 41 having a first horizontal axis. A support frame 42 that supports the support frame 42 so as to be rotatable around S4, a swivel table 43 that supports the support frame 42 so as to be rotatable, and the holding member 41 that is interposed between the holding member 41 and the support frame 42 And a turning mechanism 45 for turning the holding member 41 together with the support frame 42 about a vertical axis.

The holding member 41 includes a receiving frame 41a rotatably supported by a support frame 42. A holding frame 41a is provided on the upper surface of the receiving frame 41a so that the ladder H can be inserted from the front side of the vehicle body 1. The holding frame 41b is placed. This holding frame 4
1b is a hinge 41 with respect to the side surface of the receiving frame 41a.
The first holding member 41 is rotatably connected to the first holding member 41 via a second horizontal axis S5 which is orthogonal to the first horizontal axis S4, which is the center of the ups and downs of the holding member 41. In addition, a damper 41d is provided between the bottom of the holding frame 41b and the receiving frame 41a to reduce an impact when the holding frame 41b is turned down from an upright state. At the same time, a stopper 41f is provided upright at the end on the rotation center side of the receiving frame 41a for abutting and stopping the end of the ladder H. A stopper pin 4 for restricting the holding frame 41b from standing is provided on one side of the holding frame 41b.
1 g is provided. The tip of the stopper pin 41g is fitted into the fitting hole 4 of the upright piece 41h standing upright on the receiving frame 41a.
1i. The stopper pin 41g is urged toward the fitting hole 41i by a spring (not shown), and the stopper pin 41c is pressed against the urging force of the spring.
Is pulled out of the fitting hole 41i, the holding frame 41
b can be allowed to stand. Further, the turning means 45 includes a worm gear 45a rotatably supported by the turning table 43, a worm wheel 45b rotatably mounted on the support frame 42, and a handle for turning the worm gear 45a. 45c (see FIG. 1).

According to the ladder support means 4 having the above configuration, the lower end of the ladder H is held by the holding frame 41b while the holding frame 41b of the holding member 41 is placed on the upper surface of the receiving frame 41a. , The lower end of the ladder H can be stopped against the stopper 41f. Therefore, the ladder H can be received by the stopper 41f in a state where the holding member 41 is erected by the up / down cylinder 44. In this state, if necessary, the turning means 4
The ladder H can be used leaning against a pole P such as a telegraph pole by turning the handle 45c of the fifth member 5 to turn the ladder H together with the holding member 41 in a predetermined direction. Furthermore, by raising the holding frame 41b around the second horizontal axis S5 with the holding member 41 lying down,
By shifting the relative position between the stopper 41f and the ladder H,
The movement of the ladder H to the rear side of the vehicle body 1 can be allowed. Therefore, in this state, the ladder H is moved rearward of the vehicle body 1 while being held by the holding frame 41b, whereby the ladder H can be stored along the side surface of the vehicle body 1 (FIG. 3). reference). In this storage state, the ladder H can be prevented from greatly protruding from the front side of the vehicle body 1, so that the traveling operation of the vehicle body 1 can be easily performed. The ladder support means 4 is shown in FIG.
As shown, the lower end of the ladder H is held by the holding member 41.
And with the ladder H lying down,
To the side of each boom 21, 22, 23 in the storage position
And each boom 21, 22, 23
When turning or standing up, the ladder support means 4 and
The ladder H does not get in the way.

When the ladder H is stored, the stopper 41f may be retracted so as to allow the ladder H to move. In this case, the ladder H extends from the holding member 41 to the rear side of the vehicle body 1. If there is no obstacle that hinders the movement of H, it is not always necessary to raise the holding frame 41b around the second horizontal axis S5. Further, the hook 3 of the dodging device 3 is attached to the cable-stretched vehicle A.
The traction load detecting means 7 for detecting the traction load of the rope R hooked on the rope 1b is provided (see FIG. 6). The traction load detecting means 7 outputs a signal when the internal pressure of the cylinder 71 reaches a predetermined level with a hydraulic or pneumatic cylinder 71 interposed in the middle of the third chain E3 provided on the bending boom 23. An output pressure switch 72 is provided. In the cylinder 71, the rear end of the cylinder tube 71a is connected to one halfway end of the third chain E3, and the front end of the piston rod 71b is connected to the other halfway end of the third chain E3. It is connected. That is, when the seventh sprocket 57 is rotated by the moment acting on the dodging device 3 with the pulling of the rope R and the tension of the third chain E3 fluctuates, the cylinder tube 71a and the piston rod 7
1b is relatively displaced, so that the internal pressure of the cylinder 71 fluctuates. And this cylinder 71
Is applied to the pressure switch 72 via a pipe 73. When the internal pressure exceeds a predetermined internal pressure, the pressure switch 72 outputs a signal. The pressure switch 72 is set to output a signal when the traction load becomes, for example, 40 kgf or more.

The output signal from the pressure switch 72 is
The traveling control means 8 is configured to be input to traveling control means 8 for controlling traveling of the vehicle body 1, and the traveling control means 8 transmits a driving force of a driving source of the vehicle body 1 to the crawler 11 based on the output signal. The traveling of the vehicle body 1 is stopped by operating the clutch 13 provided in the transmission mechanism. Therefore, even when the rope R is entangled or caught while the rope R is being towed and an excessive load acts on the tip of the boom device 2, the vehicle body 1 can be prevented from tipping over.

Incidentally, the cylinder 71 constituting the traction load detecting means 7 may be interposed between the rope R and the hook 31b. Further, instead of the cylinder 71, the traction load may be detected by a load cell. In this case, the signal from the load cell is input and the determination unit determines whether the traction load has exceeded a threshold value, When it is determined that the threshold value is exceeded, a signal may be output to the traveling control means 8. Also,
When the drive source of the vehicle body 1 is a motor, the traveling control means 8 may cut off the power supply to the motor.

The vehicle body 1 is equipped with a winding device 9 for winding the rope R in a state where the rope R is hung over the support column P. The winding device 9 includes a winch 91 for winding and pulling the rope R, and a reel 92 for automatically winding the rope R pulled by the winch 91. The reel 92
Is rotatably driven by driving means (not shown), and is detachably supported on a support frame 93 erected on the vehicle body 1. The reel 92 can be rotationally driven by rotating the lever 94 in an emergency or the like.

An example of a cable stretching method using the cable-stretched vehicle A having the above configuration will be described in detail below with reference to FIGS. First, the reel 92 of the winding device 9 removed from the vehicle body 1 is rotatably disposed near a predetermined support P, and the rope R to be pulled out from the reel 92 is applied with a traction resistance to the rope R. Giving resistance machine 10
In the state of passing through 1, the tip of the rope R is hooked on the hook 31b of the dodging device 3. The resistance device 101 includes a pair of endless rotating belts that rotate with a predetermined rotation resistance. The predetermined resistance is generated by sandwiching the rope between the pair of endless rotating belts. The rope R can be paid out from the reel 92 while being given.
The resistance device 101 is used by being fixed to a support P.

In addition, before or after the work of hooking the rope R on the hook 31b of the dodging device 3, or in parallel with the work, the undulating cylinder 44 of the cable-stretched car A is operated, and the turning means 45 is turned on if necessary. By operating, the ladder H leans against the support P, and in this state, the ladder H is climbed to
Wheel F as a support member for hooking rope R
(See FIG. 9).

Next, the worker who climbed the ladder while operating the boom device 2 and lifting the rope R into the air,
The rope R is hooked on the wheel F. Thereafter, the vehicle 1 is run, and the rope R hooked on the wheel F of the support P is towed toward the support P adjacent to the support P while being held in the air (see FIG. 10). . If an aerial obstacle D such as a cable or a wire is traversing the rope tensioning space B during the towing, the vehicle body 1 is stopped when the dodging device 3 approaches the aerial obstacle D, and the boom By appropriately operating the device 2, the above-mentioned aerial obstacle D
To the annular gear 31 of the dodging device 3 through the separating portion 31a.
(See FIG. 11), the ring gear 31
Is rotated approximately 180 °. Thereby, the hook 31
The rope R hooked on b can be guided in the towing direction by passing over the obstacle D in the air. Then, the vehicle body 1 is run again to pull out the obstacle A in the air from the annular gear 31, and the annular gear 31 is reversed to return to the original position. It is led to the next support P.

Next, when the vehicle body 1 has passed the support P,
Stop the running, rest the ladder H on the pillar P again,
The climbing ladder H is climbed, the wheel P is attached to the support P, and the rope R held in the air by the boom device 2 is held.
Is hooked on a wheel drive F by a worker climbing the ladder H (FIG. 1).
2). In the same manner as described above, the metal wheel F is attached to the predetermined number of columns P, and when the rope R is hooked on the metal wheel F (see FIG. 13), the cable C is attached to the rear end of the rope R.
And the rope R is pulled by the winch 92 of the winding device 9, the rope is wound on the reel 92, and the cable C connected to the rear end of the rope R is passed through the resistor 101 from the cable reel C 1. Then, the cable C is hooked on the wheel W attached to each support P (see FIG. 14). Thereafter, by repeating the above operation, the cable C can be sequentially stretched between the columns P. The operation of hooking the rope R on the wheel W may be performed by operating the boom device 2 in addition to the case where the worker climbs the ladder H.

As described above, according to the above-described cable stretching method, the rope R is pulled in a state where it is held in the air, and is sequentially hooked on the column P, so that the cable R is once lowered to the ground and pulled by hand. Significant labor saving can be achieved as compared with the conventional stretching method in which the work of repeatedly climbing the support P and hooking the cable is repeated. In addition, even when there is an air obstacle D in the cable installation space, the aerial obstacle D can be remotely controlled by the dodging device 3, so that the installation work can be performed more efficiently.

Further, when the rope R is entangled or caught while the rope R is being towed, and an excessive traction load acts on the boom device 2, this is detected by the traction load detecting means 7, Since the traveling of the vehicle body 1 is stopped by the traveling control means, it is possible to prevent the vehicle body 1 from tipping over, and to ensure the safety of work.

Moreover, a ladder H is mounted on the vehicle body 1,
Since the ladder H can be transported while pulling the rope R, the operation of transporting the ladder alone can be omitted. The cable-stretched vehicle A according to the present invention is not limited to the above-described embodiment. For example, the cable-stretched vehicle A may be configured so that the vehicle body 1 is driven by wheels instead of the crawler 11 and the boom device 2 is raised and lowered. And the dodging device 3 is passed from a member connected to the rope R to another member opposed to the rope R with the air obstacle D interposed therebetween. Various changes can be made without directly using the cable C between the columns P without using R.

[0028]

As described above, according to the present invention, a cable or a tow rope connected to a cable can be sequentially hooked on a column while being pulled in the air, so that the cable or the rope can be lifted in the air. There is no need to repeat the work of lowering the cable to the ground, and the work of stretching the cable can be performed easily and efficiently.

Also, since the ladder is mounted on the vehicle body,
The ladder can be transported while pulling the cable or the rope. For this reason, the trouble of independently transporting the ladder is unnecessary, and the cable can be more efficiently extended. In addition, when the ladder is stored, the ladder can be moved and stored in the longitudinal direction, so that the ladder can be prevented from largely protruding from one side of the vehicle body. Therefore, it is possible to prevent the ladder from obstructing the running of the vehicle body. In addition, the ladder support means
Hold the lower end of the ladder with the holding member and fall down the ladder
The ladder and the boom in the stowed position.
With the boom swiveled.
The ladder support means and the ladder
It is easy to use because there is no risk of getting in the way.
You.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a cable-stretched vehicle according to the present invention.

FIG. 2 is a perspective view of the cable-tension vehicle shown in FIG.

FIG. 3 is a side view showing a state where the boom device is erected.

FIG. 4 is a side view showing the dodging device.

FIG. 5 is a schematic diagram showing the internal structure of the boom device.

FIG. 6 is a schematic diagram showing an internal structure of a refraction boom.

FIG. 7 is a side view showing the ladder support means.

FIG. 8 is a front view showing the ladder support means.

FIG. 9 is a schematic view showing a step of attaching a wheel.

FIG. 10 is a schematic view showing a rope pulling process.

FIG. 11 is a schematic view showing a step of dodging an obstacle in the air.

FIG. 12 is a schematic view showing a step of attaching a wheel.

FIG. 13 is a schematic diagram showing a state where a rope is stretched between a predetermined number of columns.

FIG. 14 is a schematic view showing a rope winding step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Boom device 3 Dodging device 4 Ladder support means 41 Holding member 41f Stopper 7 Traction load detection means 8 Travel control means A Cable tensioned vehicle C Cable D Aerial obstacle F Gold wheel (supporting member) H Ladder P Support R rope

Continuation of the front page (72) Yoshihisa Omura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Katsuhiko Takemura 1-2-3 Shinji, Wakabayashi-ku, Sendai, Miyagi Tohoku (56) References JP-A-3-289308 (JP, A) JP-A-4-367671 (JP, A) JP-A-59-100081 (JP, A) JP-A-4-351405 ( JP, A) JP-A 2-41607 (JP, U) JP-A 3-74743 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02G 1/00-1/06 B60P 3/14 E06C 5/00

Claims (1)

(57) [Claims] 1. A self-propelled vehicle body,A swivelable boom is installed approximately at the center in the width direction of the vehicle body.
Boom post and the boom post
And is stored along the approximate center of the width of the vehicle.
To At the end, use a supporting cable or
Connect the loopWith boomA boom device, mounted on the vehicle body, and supporting the ladder so that it can be raised and lowered and stored.
Ladder supporting means, and a ladder supported by the ladder supporting means, wherein the ladder supporting means holds the ladder movably in the longitudinal direction, and a ladder held by the holding member The lower end of the ladder
Part that stops when the ladder is retracted.
WithWith Hold the lower end of the ladder by the holding member and tilt the ladder
With the ladder in the storage position boom
Located laterally and below Cave characterized by the following:
Le tension car.